Conventionally, some proposals have been made about an in-wheel motor provided with an electric motor in an automobile wheel, and a cooling structure for such an in-wheel motor. For example, Patent Literature (hereinafter, referred to as PTL) 1 proposes a configuration in which oil is put in a casing surrounding a stator coil of an in-wheel motor to cool the stator coil.
As a technique relevant to the invention of the present application, PTL 2 discloses a configuration for cooling an electromagnetic coil by causing fluid to flow through a hollow portion of the electromagnetism coil.